Why are String and M-Theory considered scientific theories?

[Hypercube]

I've been reading a lot of articles about the whole evolution vs creationism debate (evolution all the way, by the by), and I am continually being forced to grit my teeth in frustration whenever these idiots pull the utterly vapid 'it's just a theory' argument, even though it has been explained more times than I can count that the word 'theory' in a scientific sense refers to a framework of knowledge, observations and experimental evidence that explain various aspects of reality. In other words, if the evolution scientists (I denounce any scientist that outright claims that evolution is a lie) are correct, a scientific theory is for all intents and purposes 'proven', as much as anything can be proven outside of mathematics, to be correct and accurate. That is my working definition to the word theory as well.

 

However, as much as I think the majority of creationists are just being trolls when they pull the 'it's just a theory' argument, I can't help but notice that there are several cases where scientific theories, the most obvious being String theory, M-theory, and loop quantum gravity theory, that do not fit that definition of the word theory, and seem to me to better fit the definition of theory that is a synonym of 'hypothesis', as these 'theories' have virtually no experimental evidence of any kind backing them up (if I'm wrong about that, someone please let me know). In fact I have heard several scientists refer to them as being philosophy, not science. So I'm curious, why is it that they are referred to as scientific theories and not hypotheses? True they have the potential to explain how the universe operates, but until we can build a particle accelerator the size of the solar system, we won't be able to directly test them.

Edited August 21, 2012 by Hypercube

[studiot]

Gosh a sceptic.

 

You are obviously young and were missed out in the 'pogrom'.

 

I will send the indoctrination squad round immediately.

Edited August 21, 2012 by studiot

[Ronald Hyde]

I think they have become a fad, in the same way that a dog breed becomes a fad and the breed genetics is ruined by poor breeding,

when a scientific idea becomes a fad people get sloppy and read meaning into every aspect of it. It gets so far off the track of Physics

that it has no connection with reality. Which is sad because some parts of string theory are valid physics but their meaning gets lost

in 32 dimensional spaces that have no connection with the real world.

[Antonioctd]

I don't know much about it but don't they have maths to back it up?

 

Of course math alone doesn't prove any thing. But, at least, makes it stronger than a simple philosophical hypothesis...

[Ben Banana]

A "theory" has no correlation to factual standing. Believe it or not, neither does "theorem."

[mathematic]

I've been reading a lot of articles about the whole evolution vs creationism debate (evolution all the way, by the by), and I am continually being forced to grit my teeth in frustration whenever these idiots pull the utterly vapid 'it's just a theory' argument, even though it has been explained more times than I can count that the word 'theory' in a scientific sense refers to a framework of knowledge, observations and experimental evidence that explain various aspects of reality. In other words, if the evolution scientists (I denounce any scientist that outright claims that evolution is a lie) are correct, a scientific theory is for all intents and purposes 'proven', as much as anything can be proven outside of mathematics, to be correct and accurate. That is my working definition to the word theory as well.

 

However, as much as I think the majority of creationists are just being trolls when they pull the 'it's just a theory' argument, I can't help but notice that there are several cases where scientific theories, the most obvious being String theory, M-theory, and loop quantum gravity theory, that do not fit that definition of the word theory, and seem to me to better fit the definition of theory that is a synonym of 'hypothesis', as these 'theories' have virtually no experimental evidence of any kind backing them up (if I'm wrong about that, someone please let me know). In fact I have heard several scientists refer to them as being philosophy, not science. So I'm curious, why is it that they are referred to as scientific theories and not hypotheses? True they have the potential to explain how the universe operates, but until we can build a particle accelerator the size of the solar system, we won't be able to directly test them.

My feeling is that when it comes to language in science, it doesn't have the same precision as in mathematics. The word theory can be loosely defined to include string theory, etc. More precisely these ideas can't be termed theories, since as you noted there is no experimental evidence to verify any of them.

[Hypercube]

Gosh a sceptic.

 

You are obviously young and were missed out in the 'pogrom'.

 

I will send the indoctrination squad round immediately.

 

Okay, I highly resent your veiled insinuation that I am some kind of science denier. How dare you imply that I'm some right-wing freak trying to spread decent! If that is indeed what you were implying then you are an utter moron. If anyone else here has that same impression, then allow me to dispel it here and now, because it is about as untrue as you could possibly get, and I challenge anyone to try and argue the fact!

Edited August 21, 2012 by Hypercube

[StringJunky]

I agree, these ideas shouldn't be called theories and it demeans the value of the word in terms of evidential weight associated with it scientifically to call them that. It also puts them on par with the likes of SR and GR et al when they aren't...it's a sloppy attribution. I dare say someone will chime that although there is no evidence to support them the maths is very pretty.

[Ronald Hyde]

I dare say someone will chime that although there is no evidence to support them the maths is very pretty.

 

I totally agree on that one. Many have been tempted into believing them a valid physical theory because of the 'pretty maths'.

[Hypercube]

I don't think they're necessarily wrong, but they certainly aren't anywhere close to being on par with something like evolution.

[StringJunky]

I don't think they're necessarily wrong, but they certainly aren't anywhere close to being on par with something like evolution.

 

Just to be clear,I wasn't implying they were wrong...they just don't have any evidence as yet, or even if they will, and so don't at the moment deserve the 'theory' tag.

[studiot]

Okay, I highly resent your veiled insinuation that I am some kind of science denier.

 

 

Well I'm sorry if you took it that way.

 

 

I meant that you seem skeptical of string theory and mtheory (as I am), not science in general.

 

 

 

go well

[Hypercube]

Well I'm sorry if you took it that way.

 

 

I meant that you seem skeptical of string theory and mtheory (as I am), not science in general.

 

 

 

go well

 

I'm am skeptical by nature, as are all true scientists. And if that was all you were trying to imply than you shouldn't have used the 'indoctrination squad' card. What else was I supposed to take that to mean?

[ajb]

So I'm curious, why is it that they are referred to as scientific theories and not hypotheses?

 

Theory here should probably be better understood as a "body of knowledge" (as it would be in mathematics) or a "mathematical framework".

 

String theory itself (for example) should be thought of as a highly non-trivial generalisation of point-particle quantum theory to 1-d extended objects (and of course we need branes). This framework has many motivations and many interesting features, but right now it is just that; a general mathematical framework.

 

Really just as general relativity is, for example. Apart from rather generic features, one needs to look at particular solutions of the field equations to extract the physics.

 

The trouble with string theory is there is too many solutions and no way to decide which ones are relevant to physics. This is the string landscape problem.

 

M-theory, which encompass string theory is more elusive. Plenty is known about M-theory, but plenty of open questions remain, such as identifying the fundamental degrees of freedom.

 

Anyway, take "theory" to mean "mathematical framework" and we are okay. I would then understand "physical theory" to be a particular solution or set-up within a mathematical framework. For example, the standard model of particle physics describes the known forces of nature apart from gravity to some high degree of accuracy. The framework behind this is quantum field theory, which is much more general than the standard model and one can easily consider models within this that are unphysical.

[Antonioctd]

I'll take this chance to clarify something...

 

First I'll say that I'm a musician! I just curious about the world and reading about physics gives me some answers.

 

So, if my question is stupid... well... forgive me!

 

My question:

 

Mathematics is an exact science.

Some say that it is the language of the universe.

 

I don't know much math but I can see that, if I know from math that 2+2=4, I don´t ever need to experiment and actually put together 4 objects and count them.

 

My point is, If it works in math it should work in the real world. Right?

 

If it doesn't work, all the math must be wrong!

As if the math was saying 2+2=5 and then I do the experiment and actually put 2 objects next to other 2 and count 4!

 

In that case is the math that is wrong. Not my theory!

[imatfaal]

I'll take this chance to clarify something...

 

First I'll say that I'm a musician! I just curious about the world and reading about physics gives me some answers.

 

So, if my question is stupid... well... forgive me!

 

My question:

 

Mathematics is an exact science.

Some say that it is the language of the universe.

 

I don't know much math but I can see that, if I know from math that 2+2=4, I don´t ever need to experiment and actually put together 4 objects and count them.

 

My point is, If it works in math it should work in the real world. Right?

 

If it doesn't work, all the math must be wrong!

As if the math was saying 2+2=5 and then I do the experiment and actually put 2 objects next to other 2 and count 4!

 

In that case is the math that is wrong. Not my theory!

 

Antonio - the problem is not that the maths is wrong, it is finding the correct maths to use. No mathematicians would argue over how y=1/x and y=1/(x^2) and y=1/(x^3) vary as x gets bigger from 1 - the connection with physics is that only one of those equations is similar to how gravity varies as you get further away from the central mass.

 

It is easy (well actually it isn't come to think of it) to create a consistent mathematical framework that provides predictions for physical variables - the real headache is producing a mathematical framework that fits with nature.

 

I could take your simple 2+2 = 4 and make the following statement - there are 2 planets of the solar system inside earth's orbit and 2 outside earth's orbit therefore the maths confirms that there are only 4 planets other than earth in the solar system. And no matter how much I defend the maths - the whole thing is nonsense because I stopped counting at Jupiter! The challenge for modern physics is linking the incredibly huge data set (which is diverse yet interconnected) with a mathematical framework (which cannot include self-contradictions)

[ajb]

Mathematics is an exact science.

Some say that it is the language of the universe.

 

I would agree with this, but be warned there is a debate about mathematics being a science or not.

 

I don't know much math but I can see that, if I know from math that 2+2=4, I don´t ever need to experiment and actually put together 4 objects and count them.

 

Okay, for this simple example you are right. However, in practice one may discover important things first by examining specific examples. Mathematics is not always done via reductive reasoning ("start general get to examples"), but rather more often it is done via inductive reasoning ("start from examples to get at the general").

 

So, by "experiment" in mathematics one could mean "examine examples", maybe even numerically. Finding one counter example would falsify your mathematical claims.

 

Of course, mathematicians rather have watertight theorems that cover large classes of objects. However, getting at these may come from understanding lots of "experiments".

 

 

My point is, If it works in math it should work in the real world. Right?

 

As already stated by another member, the mathematics maybe right, but how is is applied in the physical world maybe wrong. You can certainly construct models that are unphysical in the sense that they do not agree with nature well.

 

Quite often as a mathematical physicist one is happy working with simple models that have little relation to nature if they allow you to explore the mathematical features of potentially more realistic models.

 

It is easy (well actually it isn't come to think of it) to create a consistent mathematical framework that provides predictions for physical variables - the real headache is producing a mathematical framework that fits with nature.

 

Quantum field theory is quite an enigma from that point of view. Interacting theories may not be well defined, perturbation series don't necessarily converge and then we have remormalisation. from a mathematician's view point quantum field theory is generally quite a mess.

 

Yet is forms the basis of the standard model of particle physics...

[imatfaal]

Quantum field theory is quite an enigma from that point of view. Interacting theories may not be well defined, perturbation series don't necessarily converge and then we have remormalisation. from a mathematician's view point quantum field theory is generally quite a mess.

 

Yet is forms the basis of the standard model of particle physics...

 

 

It's way beyond my pay-scale - but was this not one of the bases of string theory; that they were not going to compromise mathematically and end up with a working but inconsistent group of (semi-)contradictory models. And that the maths of string theory - whilst mindbogglingly tough - is beautifully consistent - it's the marrying up that single system with the real world that is the problem

[ajb]

It's way beyond my pay-scale - but was this not one of the bases of string theory; that they were not going to compromise mathematically and end up with a working but inconsistent group of (semi-)contradictory models. And that the maths of string theory - whilst mindbogglingly tough - is beautifully consistent - it's the marrying up that single system with the real world that is the problem

 

Point-particle QFT uses Feynman diagrams which are graphs. One should think of the vertices of these graphs as being the root of the infinities and the reason why renormalisation is required.

 

In string theory these graphs get replaced with surfaces, which removes these infinities.

 

Sting theory is finite from the start and one of the motivations for study.